Streetlight Strategies

How Yellowknife’s ravens turn up the heat

story by Brad Heath | illustration by Alison McCreesh

It was -52 (with wind chill) on a bitterly cold December morning when I noticed a frosty raven hunkered down on a streetlight shining on Franklin Avenue, even though the sun was visible through ice fog. I’ve often heard Yellowknifers speculate that ravens have learned to stay warm by perching on the streetlights – that they know how to turn them on. I wondered, could this be true?

A chat with Kevin Lailey, operations superintendent at Northland Utilities in Yellowknife, provided a definitive answer: Yes. It’s true! Ravens (and gulls) are indeed turning on streetlights, and creating heat by manipulating the photocells on top of the lights.

Lailey showed me one of the photocells. It’s a bit smaller than two hockey pucks stacked, grey in colour and attaches to the top of a streetlight with a twist-lock plug. It also features a small, clear plastic window on the side that allows light to reach the photoelectric sensor within.

When a raven perches on the photocell, its large black body blocks light from reaching the photoelectric sensor, and that activates a flow of electricity that turns on the streetlight – creating radiant heat for the ravens.


Lailey says ravens have also learned to peck through the plastic window and damage the photoelectric sensor, causing the streetlight to stay on 24/7 – until a Northland repairman makes a visit.

Alas, this free source of heat will be greatly diminished by the end of 2016. Northland Utilities is, at the request of the City of Yellowknife, converting all high pressure sodium (HPS) lights to energy saving light-emitting diode (LED) lights.

There’s no need, however, to worry about Corvus corax. Yellowknife naturalist and Weledeh MLA Bob Bromley says the Common Raven has a high body temperature and great insulation – and they’re so adaptive that they will find other sources of heat when needed.

If you are wondering why Yellowknife’s streetlights are not crowded with ravens jostling for a warm perch after dark, that’s because they fly to communal roosting sites for the night. And where are these roosts? Well, that’s a question perhaps best explored in warmer temperatures when neither reporter nor ravens need worry about freezing feet.


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